I just got fit for the Mizuno Pro 243 with the Recoil 460 F3 shaft

[Chipshot56]

Currently playing the Mizuno Pro 223 with the Nippon 950GH regular steel shaft and love them. Unfortunately getting older and want to keep up the swing speed and gain height while increasing the decent angle (currently 37 - 38). I just got fit for the 243's with the Recoil 460 F3 graphite shaft. it did get my height up about 10 feet (mid 60 feet to mid 70) picked up a couple yards of carry and about 500 in spin. The decent angle bumped into the low 40's. I'm dying to know if I should/could expect the same results if I simply put that same graphite shaft in my current 223 irons? My question is whether I should reshaft my 223's with the recoil shaft (which I did not get a chance to hit) or just buy the 243's. Difference in cost is $300 vs $1400! Help Please!!!